These images are a composite of separate exposures acquired by the ACS and WFC3 instruments on the Hubble Space Telescope. Several filters were used to sample narrow wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are:

This sea of approximately 15,000 galaxies — about 12,000 of which are forming stars — is one of the most comprehensive portraits yet of the universe’s evolutionary history. The ultraviolet vision from NASA’s Hubble Space Telescope, combined with infrared and visible-light data from Hubble and other space and ground-based telescopes, opens a new window on the evolving universe. It tracks the birth of stars over the last 11 billion years back to the cosmos’ busiest star-forming period, which happened about 3 billion years after the big bang.

Ultraviolet light has been the missing piece to the cosmic puzzle. Because Earth’s atmosphere filters most ultraviolet light, Hubble can provide some of the most sensitive space-based ultraviolet observations possible.

This image straddles the gap between the very distant galaxies, which can only be viewed in infrared light due to the expansion of the universe, and closer galaxies, which can be seen across a broad spectrum. By comparing images of star formation in the distant and nearby universe, astronomers gain a better understanding of how nearby galaxies grew.

The program, called the Hubble Deep UV (HDUV) Legacy Survey, extends and builds on the previous Hubble multi-wavelength data in the CANDELS-Deep (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) fields within the central part of the GOODS (The Great Observatories Origins Deep Survey) fields. This mosaic is 14 times the area of the Hubble Ultraviolet Ultra Deep Field released in 2014.

This image is a portion of the GOODS-South field, which is located in the southern constellation Fornax.